Prostanoids comprise prostaglandins (PGs) and thromboxanes (Txs) and their receptors fall into five different classes (DP, EP, FP, IP and TP) based on their sensitivity to the five naturally occurring prostanoids, PGD2, PGE2, PGF2a, PGI2 and TxA2, respectively (Coleman, R. A., Prostanoid Receptors. IUPHAR compendium of receptor characterisation and classification, 2nd edition, 338-353, ISBN 0-9533510-3-3, 2000). EP receptors (for which the endogenous ligand is PGE2) have been subdivided into four types termed EP1, EP2, EP3 and EP4. These four types of EP receptors have been cloned and are distinct at both a molecular and pharmacological level (Coleman, R. A., 2000)
EP2 agonists have been shown to be effective in the treatment of a number of conditions, including (but not limited to) dysmenorrhoea (WO 03/037433), pre-term labour (GB 2 293 101), glaucoma (WO 03/040126), ocular hypertension (WO 03/040126), immune disorders (Nataraj, C., at al., J. Clin. Invest., 108, 1229-1235 (2001)), osteoporosis (WO 98/27976, WO 01/46140), asthma (Tilley, et al., Am. J. Physiol. Lung Cell Mol. Physiol., 284, L599-606 (2003)), allergy, bone disease (WO 02/24647), fracture repair (WO 98/27976, WO 02/24647), male sexual dysfunction (WO 00/40248), female sexual dysfunction (U.S. Pat. No. 6,562,868), periodontal disease (WO 00/31084), gastric ulcer (U.S. Pat. No. 5,576,347) and renal disease (WO 98/34916).
In co-pending applications GB 0329620.9, filed 22 Dec. 2003 and a corresponding US provisional application filed 24 Dec. 2003, which are hereby incorporated by reference, it has been shown that EP2 agonists inhibit lymphocyte activation and the release of pro-inflammatory cytokines from alveolar macrophages. In addition, EP2 activation inhibits monocyte and neutrophil activation. Thus, EP2 agonists should prove useful in the treatment of inflammatory and immune disorders such as psoriasis, dermatitis, rheumatoid arthritis, multiple sclerosis, scleroderma, transplant rejection, allergy, systemic lupus erythematosus, vasculitis, type 1 diabetes mellitus, and inflammatory lung diseases such as chronic obstructive pulmonary disease, asthma, acute respiratory distress syndrome and cystic fibrosis.
In addition, EP2 agonists can also be used in the treatment of fibrosis, including, but not limited to idiopathic pulmonary fibrosis, scleroderma and systemic sclerosis, post-operative fibrosis following trabulectomy, liver repair and regeneration following cirrhosis, hepatitis, toxicity, cancer or renal fibrosis. EP2 agonists can also be used in the prevention of fibroblast to myofibroblast conversion to treat asthma and other fibrotic lung diseases. EP2 agonists may also be used to maintain ductus arteriosus patency in infants with congenital heart disease.
Compounds which combine EP2 receptor agonist and EP4 receptor antagonist properties may prove useful in the treatment of several diseases including myometrial disorders, bone diseases including osteoporosis and osteoarthritis, allergic and immune disorders such as psoriasis, transplant rejection, and asthma, inflammatory diseases such as rheumatoid arthritis, chronic obstructive pulmonary disease and acute respiratory disease syndrome, and fibrotic lung diseases.